Problem: If $x \bigtriangleup y = x+4y$ and $x \odot y = 4x-7$, find $(-2 \odot -2) \bigtriangleup 2$.
Solution: First, find $-2 \odot -2$ $ -2 \odot -2 = (4)(-2)-7$ $ \hphantom{-2 \odot -2} = -15$ Now, find $-15 \bigtriangleup 2$ $ -15 \bigtriangleup 2 = -15+(4)(2)$ $ \hphantom{-15 \bigtriangleup 2} = -7$.